PXS20RM Datasheet, PDF (536/1368 Pages) Freescale Semiconductor, Inc – PXS20 Microcontroller

Fault Collection and Control Unit (FCCU)
— SAFE mode request (delayed)
• Chip mode transition: RUN  SAFE
• NMI interrupt management
— FAULT recovery (by SW): FCCU state transition FAULT  NORMAL
— System state transition: SAFE  RUN
Non-critical fault event
SW FAULT recovery
Chip mode
RUN
SAFE
RUN
FCCU state
Alarm interrupt
request
NCF Timer
Short or long ‘functional’
reset request
SAFE mode request
NORMAL
IDLE
ALARM
FAULT
TIMER ON TIMEOUT
NORMAL
IDLE
NMI
FCCU_F
IDLE
ERROR ON
IDLE
FCCU reset
Figure 22-32. Non-critical FAULT (ALARM -> FAULT state) recovery
A typical sequence related to a critical FAULT (with nesting) management, given in Figure 22-33, is
following described:
• Critical fault assertion (no short or long ‘functional’ reset)
• FCCU state transition (automatic): NORMAL  FAULT
— NMI assertion
— SAFE mode request (delayed)
• Chip mode state transition: RUN  SAFE
• Critical fault assertion
— Short ‘functional’ reset
• Chip mode transition: SAFE  RESET
• NMI interrupt management
— FAULT recovery (by SW): FCCU state transition FAULT  NORMAL
22-36
PXS20 Microcontroller Reference Manual, Rev. 1
Freescale Semiconductor